for Health Care Providers
Epidemiology of Hepatitis C
Prevalence of Hepatitis C Infection in the General Population in the United States
The hepatitis C virus (HCV) is an RNA virus classified within the Flaviviridae family.(1) Before the characterization of the virus, a diagnosis of viral hepatitis was largely one of exclusion (ie, non-A, non-B hepatitis). Early studies demonstrated that non-A, non-B hepatitis was associated with blood transfusions.(2,3,4) Population-based sentinel surveillance conducted by the Centers for Disease Control and Prevention demonstrated that this disease accounted for 15% to 20% of community-acquired viral hepatitis in the United States.(5) After the virus was cloned in 1988, studies demonstrated that HCV was the primary cause of community-acquired non-A, non-B hepatitis in the United States.(5,6) Data from the Third National Health and Nutrition Survey (1988-1994) estimate that there are approximately 3.9 million non-institutionalized, civilian Americans who have been infected with HCV.(7) Of these, 2.7 million have chronic infection, making HCV the most common chronic blood-borne infection in the United States. Perhaps the majority of those infected are unaware of their infection because they do not currently have signs or symptoms of disease. The highest prevalence of infection is found among those with repeated, direct percutaneous exposures to blood (eg, injection drug users, recipients of blood transfusions from HCV-positive donors, and persons with hemophilia who were treated with clotting factor concentrates before 1987). The estimated prevalence of infection varies greatly among different geographic locations and selected populations in the United States according to the varying prevalence of risk factors for infection.
Prevalence of Hepatitis C Infection in Veterans
The true prevalence of hepatitis C infection among veterans is unknown, but survey data suggest that hepatitis C has a higher prevalence in veterans who are currently using the VA system than in the U.S. population as a whole. Data from the National VA Screening Day in March of 1999 demonstrated that 6.6% of veterans who had blood drawn for other purposes on that day were HCV seropositive(8). In a recent study published by Sloan et al, 37,398 veterans from the VA health care system in the Pacific Northwest were tested for anti-HCV antibodies, and 8,230 (21.7%) were positive.(9) 45.8% of the seropositive veterans were between the ages of 40 and 49 years. The prevalence of anti-HCV among male US shipboard military personnel scheduled for deployment to South America/West Africa and the Mediterranean was approximately 0.4% (9/2072)(10). The prevalence of anti-HCV among a cohort of active-duty US marines stationed in Okinawa, Japan was 0.2% (2/1010).(11) Therefore, the prevalence of antibodies to HCV varies substantially according to the different military populations considered. In general, the prevalence in active duty military personnel appears to be lower than the prevalence in veterans.
- Simmonds P, et al. Classification of hepatitis C virus into six major genotypes and a series of subtypes by phylogenetic analysis of the NS-5 region. J Gen Virol 1993;74:2391-9.
- Alter HJ, et al. Detection of antibody to hepatitis C virus in prospectively followed transfusion recipients with acute and chronic non-A, non-B hepatitis. N Engl J Med 1989;321:1494-500.
- Aach RD, et al. Hepatitis C virus infection in post-transfusion hepatitis: an analysis with first- and second-generation assays. N Engl J Med 1991;325:1325-9.
- Alter MJ, et al. The natural history of community-acquired hepatitis C in the United States. The Sentinel Counties Chronic Non-A, Non-B Hepatitis Study Team. N Engl J Med 1992;327:1899-905.
- Centers for Disease Control and Prevention. Recommendations for prevention and control of hepatitis C virus (HCV) infection and HCV-related chronic disease. MMWR 1998;47(RR-19):1-39.
- Alter MJ, et al. Risk factors for acute non-A, non-B hepatitis in the United States and association with hepatitis C virus antibody. JAMA 1990; 264:2231-5.
- Alter MJ, et al. The prevalence of hepatitis C virus infection in the United States, 1988 through 1994. N Engl J Med 1999;341:556-562.
- Kralovic SM, et al. National Hepatitis C Surveillance Day in the Veterans Health Administration of the Department of Veterans Affairs. Mil Med 2002;167:756-759.
- Sloan KL, et al. Hepatitis C tested prevalence and comorbidities among veterans in the US Northwest. J Clin Gastroenterol 2004;38:279-284.
- Hawkins RE, et al. Risk of viral hepatitis among military personnel assigned to US navy ships. J Infect Dis 1992;165:716-719.
- Brodine SK, et al. The risk of human T cell leukemia virus and viral hepatitis infection among US marines stationed in Okinawa, Japan. J Infect Dis 1995;171:693-6.